The present invention relates to band printers containing a rotating exchangeable type carrier with sensible timing marks and with a sensible mark to determine the start of control processes for character generation.
The IBM Model 3262 steel band printer uses rotating type bands with etched characters and timing marks. A stationary sensor is used to detect the timing marks on the rotating band and the number of pulses produced during the sensing are counted relative to a pulse produced by a starting mark to identify the character in the print position. In the 3262 printer, the starting mark is a missing timing mark, so that the sensing of the starting mark is accomplished concurrently with the sensing of the timing marks.
The type bands of a steel band printer are exchangeable, so that bands with different character sets can be used and old bands can be replaced by new ones. Data as to the particular kind of type band being used must be entered into the printer before the printer can be properly operated.
In the IBM model 3262 printer, type band identification is effected by a manual procedure. After the type band has been inserted in the printer a sample print-out is made which permits a visual identification of the type band. Then a switch is manually activated to identify the type band to the electronics of the printer system.
This kind of type band identification is time consuming, complex and unreliable.
German patent application OS No. 25 00 263 shows a printer system with an automatic type band identification system. The type band has a binary-encoded band identification mark arranged on a separate track from the timing signals. This arrangement is complex, since it requires an additional marker track and an additional sensor and amplifier.